[gmx-users] first residue in chains warning issue

Justin Lemkul jalemkul at vt.edu
Mon May 18 13:44:02 CEST 2015

On 5/18/15 7:39 AM, Ming Tang wrote:
> Dear Justin,
> After minimization, I got the following note when using NPT.
> NOTE 1 [file topol.top, line 49]:
>    The bond in molecule-type Protein_chain_A between atoms 1 N and 2 H1 has an estimated oscillational period of 1.0e-02 ps, which is less than 10
>    times the time step of 1.0e-03 ps.  Maybe you forgot to change the constraints mdp option.
> Does this has something to do with the warning given by pdb2gmx?
> When reducing dt from 0.001ps to 0.0009ps, the note is gone. Is there anything wrong with my topol.top?

No, as the note says, you probably aren't using constraints, which if you want a 
1-fs or larger value of dt, you need to be using.



Justin A. Lemkul, Ph.D.
Ruth L. Kirschstein NRSA Postdoctoral Fellow

Department of Pharmaceutical Sciences
School of Pharmacy
Health Sciences Facility II, Room 629
University of Maryland, Baltimore
20 Penn St.
Baltimore, MD 21201

jalemkul at outerbanks.umaryland.edu | (410) 706-7441


More information about the gromacs.org_gmx-users mailing list